But the opposite is the case. The sun will get hotter for the foreseeable future until the earth will also become uninhabitable. And then the sun will expand an

But the opposite is the case. The sun will get hotter for the foreseeable future until the earth will also become uninhabitable. And then the sun will expand and swallow Venus and probably also our planet. So if we base the choice only on the expected future intensity of the sun Mars would seem the better choice.